Fluid-pressure gauge



Dec. 11, 1923.

E. LETSCH FLUID PRESSURE GAUGE Filed June 29. 1921 ATTORNEYS Patented Dec. 11,1923.

3 In the drawings: a Fig. 1' s a face view of a pressure gauge embodyingthe'varh "ousfeatures of my invention a I Fig. 2 is a perspective viewof the interior 7 1 UNI D TA E IJPATENT OF EUGENE LETSCH, or Lym'moox,

1,476,896 FICE."

NEW YORK, ASSIGNOBTO PIERCE, BUTLER &: PIERCE more. (2032., or sx mcusa, NEW YORK, A CORPORATION or NEW Yoaxi rnurn-ranssuan GAUGE.

lpplicatiomfiled June 29, 1921.; Serial No. 481,246;

Torall whom it may concern:- 5 V Be it known that I, EUGENE LETSCHy-Of Lynbrook, in the county of Nassau in the State of New York, have invented new and useful Improvements in Fluid-Pressure Gauges, of which the following, taken .in connection with the accompanying drawings, is a full, clear, and exact description.

Thisinvention relates to afiuid pressure gau e in which apressureactuated tube of the ourdon type. is employed in the, operation of an index finger or pointer around a graduated dial calibrated to indicate the pressure in the tuba Thefiuid underpressure whether liquid purposes but in almost all instances is utilized within certain limits or rangeofpres sure with more or less frequent fluctuations; above the normal range, and the main object of my present invention is to provide simple and efiicient'meansfor registering the normal pressures most commonly used over a relatively widefield or relatively long are upon the dial and-for registering; the ab-' normal or reserve pressures through, a relatively narrow field or short are of the dial,

thereby permitting a relatively wide spacing the movement of the index finger or pointer through a relatively long are for normal .1 working pressures andthrough, a relatively short are for extra or reserve pressures whereby to enable the fattendant to, obtain clear and accurate readingsof the lowerunit working pressures and approximate read.

ing; of the higher pressures.--

her ob'ects and uses relating to specifics parts of the device will be brought out in the followin d ri ti n; 7 a i mechanism of the gauge omitting thecase taken,

and dial and portions ofthe. expansion tuber Figs. 3 and fare detailed sectional-views or gaseous may be used for many differentpartlybroken away i a thepointer operating mechanism respectively; on Iines 3- 3 and 4+4 7 through the passage-way 1n the extension As illustrated, the pressure gauge comprises a cylindrical case or housing --.-1-, a circular dial plate -2--, an index finger or pointer. 3 a dial supporting frame and means for moving the pointer around the dial as hereinafter more fully described. 1

The case orvhousing 1 is provided at .its lower side with a segmental platform 4-- for receiving and'su-pporting the in ner frame and mechanism carried thereby,

and is preferably open at the front side for receiving thedial plate which is preferably secured to the frame independently of .thecasing to enable the'working parts to be roperly adjusted before being installed in the case or housing. 7 v

1 The frame preferablycomprises a supporting base 5' secured by screws -6 to the platform and adjacent sideiof the case and is provided with'a tubular extension 7- projecting through a radial openin said platform andcaseto the exterior thereof and having its outer end threaded I for securement to a conduit or otherfpa-rt of the fluid pressure'sy'stem.

A pair of similar uprightplates 8-8 are secured at their lower ends by screws -9 to the front and rear faces of the base -5- and extend upwardly therefrom in substantially parallel planes and are additionally held in fixed spaced relation by trans verse tie rods or posts -10V-, 11;and 12-, the posts 10 and --11 being located near the base .'5--, while the post -12- -,is located near the upper ends of the platesi.;8 some distance above the posts lO- and "11-. 1 v

i The dial plate -2.- issecured by screws -13:- tothe front'face of the front plate l+8-- and is provided with a central aperture through which the adjacent end of the pointer supporting spindle projects to allow said pointer to be secured to the outer end thereof to move'around the front face of the'dial so that the' several adjustments of the pointer operating means may be more conveniently made before the frame with installed in the case.

Pointer:Operati g-Mechanism! thereon are 7 munication with the pressure. system" the other end of said 'tube being 7 closed rand ipivotally' connected by a 3 link "to one end of a sectional lever l6- I raving a plurality of, in this instance two,

r gf nlcrnmsi upon theaupwardly extending plates -+'8nand itseother end pivotally connected'by a- 'link -17 to a sectional toothed segment -18- meshing-with pinion '1 9, the latter being secured to a spindle -20 having its ends jou'rnaled in the plates -8- for receiving and support- I ing the Epointer -3 on the "front end thereot" V T-he' lever;%1-6' is oneend'ofQthe-link 15 a nd has its op- Y :"piosite end adjustable lengthwise of and 2 by clamping screws 2etwvhich'are'passed through a len'gthwise' slot in the-secfltion-e fi and engaged'i'n threaded a'per' V tures" in Y the; section 22 thnsjpermitting c thelengthening or shortening of the lever-- age connection'with thefreevenclof the tube -14 as"may be necessary to conform 'to difierent coefiilc'ient so f travel of different 1 tubes DWIDg to their variations in res1liency.

v elongated'slots 27 and 28,"Fig'ure V "2, inlong'itndinallyspacedrelation betiveen I 3 'thefpiw' ots -'23 and '+"26' 'f0r receiving the "fulcrum stu'ds or {posts "10' and --11*,- respectively, the {other end 10f said 'tracting sprin 29+ to the adjacent por- 40 tion'of the base 5, for normally holding theupper wvall'oftheslot -'2T"in contact and simultaneously holding thelovver Wall of theslot 28-- in engagement with the fut The toothed'segment is pivot edfat -30 to" the; upright plates and is gu'ithj a lengthw ise slot '3 3- for receiving the' pivotal pin and a clamping screw tension ;3l-in its adjusted position.

The object or this last"namedadjustment I '3 igt to enable the" pointer" to travel thronghits maximum rangeof 'jmovement around the able bearingimember,735 Figures 1 and 3 is pivotally mounted upon the lever sec lengthwise of said slotor transversely of the lever section +22% to cooperate with the adjustment-of: thelever sections 2l--- and 22 in changing the leverage of the lever -l6- at-the -criticalmoment. or at the endof the longer range of movement of the pointer to cause the latter to change its angleiot movement through a cmisideralily shorter range, for the same or greater movement-oi? thefree end of the Bonrdon tube.

As illustrated, 'the maximum range of "movement of the pointer is through an are considerably greater than halt a circle. as indicated upon the'diahwvhi'ch is graduated along said are by a seriesof. in this instance, ele\'*en transverse division lines in substant1ally uniiform spa'ced relation, ten of which are Dumbered in sequence from zero to ten,

representing units of pressure as pounds, 3

per square inch, and represent the normal.

or usual working pressure. while the re maining-space issub-dividedfhv a medial line-and 'represents the abnormal, or relatively high reserve pressure of. in this in stance; from ten to thirty; pounds per square inch, or other units otpressure.

When thevai'ionsparts are properly adju'sted, the position of the fulcrum pins 10- and '11-, relatively to each other, and to'the'pivotal'pins '-i3 and -2t' is such that acertain amount of movement of; the tube 14-- from its normal position ot'rest, will cause therotation ol the pointer -3- from its zeroposition through sulv stantiallyten elevenths of-its maximum are 7 r of'movement'about' the axisgof the" fulcrum lever section 22j being connected'by repin l0-','at' which time, if the pressure continues to increase, the fulcrum of'lhc lever 16- will be automatically shifted 'from'thc pin 10"to thepin -,l11, the pull of thespring 29-heing overcome by the increased force which is exerted by the tube 14t and an increase of the distance.

"o'r'thiee times the pressure required to pro duce that movement of the pointer, will cause said pointer to move only one-eleventh orthrongh the remaining portion of said are of maximum "movement of the pointer. That is; the spring '29hnor1nally holds the lever 16' in engagement with the fulcru'mpin ''10 a'relatively short distance from its connection u ith'the free end of the tube 'I 1 and maintains this position dnr- *ing'the relatively low, pressure of, in this instance, from zero to ten pounds per 5 uare inch, during which the'longer arm 0 the V lever connected" to the toothed segment 7 dial "to j prope'rly *registerf' with jthe {indices' I thereon according to the pressure. -A suit- -'18 will, 'of 'course, move in a relatively longer are than-lthefir'stnamed'end as conn'ectedn iththe'tube, and will cause the pointer to move in a' corresponding are, of in-this instancepfrom ze'r'oto ten, it being N understoodthat the "slot -28-- is of sufli- $5 be'aring oriiEthiaStudQ-l1 and is a djustiible cient length to 'permit that movement, and

that the adjustable bearing member -35 is adjusted by hand and clamped in its aid justed position'by a pivotal bolt -35- to engage the fulcrum pin 11- at the end of such movement, thereby limiting the first named movement of the lever upon the fulcrum -10- in case the pressure in the tube should continue to increase, in which case, it is obvious that the lever would then swing upon the fulcrum -11- which is a rela tively short distance from the pivotal connection of said lever with the link -17.

This shifting of the fulcrum of the lever -16 from the pin 10- to thepin -11- allows the end of the lever connected to the tube 14.- to move through a longer are than its opposite end to correspond to the increased movement of the tube clue to the increased pressure therein, While the shorter ii arm of the lever from the fulcrum --11- to the connection With the toothed segment l8 moves through a relatively short arc, and produces a correspondingly short are of movement of the pointer 3- to indicate the relatively high or reserve pressure, until limited by the lower Wall'of the slot 27- engaging the fulcrum 10-, this latter slot being of sufficient length to permit the move- 7 ment of the pointer through the maximum range of the gauge.

As the pressure in the tube is reduced below the highest point of'the Working range, in this instance, .ten pounds per square inch, the fulcrum of the lever -16' is restored from the fulcrum pin -1'1' to the fulcrum pin l0- by 'means of a spring ,-29, which also serves to return the lever and pointer, together With the intermediate connection, to their normal, or starting position, when the pressure is reduced to a minimum, or to the zero graduationJ I claim:

1. In a fluid pressure gauge, means actuated by the fluid pressure for indicating variations in said pressure, including a lever having different fulcrums and means Whereby it'is actuated on one fulcrum by pressure 2 Within a certain range, and on another fulcrum by pressures above that range.

2. In a fluid pressure gauge, a lever, separate fulcrums for said lever, means actuated by fluid pressure Within a certain range for rocking the lever about one fulcrum and about the other fulcrum when the pressure exceeds that range. V I

3. In a fluid pressure gauge, a lever, separate fulcrums for said lever, means actuated by fluid pressure within a certain range for rocking the "lever about one fulcrum and about the other fulcrum when the pressure exceedsthat range, said lever having one of its fulcrum-bearings adjustable to vary the period of engagement with that fulcrum.

4. In afluid pressure gauge means actuated by the fluid pressure for indicating variations in said pressure,'including a lever having different fulcrums and means Where-'- by it is actuated on one fulcrum by'pres sure Within a certain range and'on another fulcrum by pressureabove that range, said lever having a longitudinally adjustable section for varying its arc of movement.

5. In a fluid pressure gauge, a dial, a pointer movable around the dial, a lever movable about a fulcrum and having an independent movement transversely thereof, pressure-operated means for rocking said lever, means for transmitting motion from the lever to the pointer, and a stop for limiting the movement of the lever on said fulcrum and forming another fulcrum on which the lever may rock transversely of the first named fulcrum. I j v In .witness whereof I have hereunto set my hand this 16th day'of June 1921.

EUGENE LETsoH. Witnesses W. E. GILLEN, FRED O. Punnr. 

